"I read an issue of preacher after reading the Weekly review here. I enjoyed it. Then I bought more. It was fun. I wish I could find another series that was fun like Preacher. Cells are bad. My uncle lives in a cell. It's ten foot by twelve and he has to read the same old boring magazine everyday. The end."

It's Miyazaki, if that's worth anything to you, so it's not going to be your typical Naruto power-level "BELIEVE IN YOUR FRIENDS!" bullshit.

You probably already have heard of these, but also check out:
Transmetropolitan (especially if you like Preacher)
The League of Extraordinary Gentlemen
Y The Last Man
Akira
Dark Knight Returns if you can stand the horrible art

HOLY SHIT GW I'VE BEEN TRYING TO FIGURE OUT WHAT THE HELL COMIC I COULD'T REMEMBER WAS, IT WAS TRANSMETROPOLITAN YOU ARE OFFICIALLY ON THE GUS GOLD LIST

Really don't know about dark knight returns, since I HATEATEATEHATED sin city, which was supposed to be miller's best work by leaps and bounds. also really, really confused about LOEG. I was going to buy that "black dossier" hardcover special edition whatever-it-was (don't ask) off amazon, when a couple other students saw me about to do it and told me not to, since it was fucking terrible. I thought League was universally supposed to be good

Dark Knight Returns is miles better than anything in Sin City, I thought, but if you don't like Frank Miller, forget it.

League of Extraordinary Gentlemen Volumes 1 and 2 are fantastic, but I haven't read that Black Dossier thing or the newest one, Century 1969. I hear it's gotten a little bit insane as of late; one of the antagonists in 1969 is Tom Riddle from Harry Potter. Bluh?

Black Dossier is a midquel to fill space between Vol. 2 and the current running Vol. 3. All it does is explain some more backstory to the universe. If you buy Vol. 1 and 2, you won't really be reading anything too new. All the back stories in it is way more interesting than the storyline that occurs around it all, though. It has a lot of sex, and I mean A LOT of sex, so get ready for that.

Edit: ALSO CONSIDER:
Berserk: Insanely violent and awesome fantasy comic about a badass motherfucker cursed to be hunted by every demon in the universe until he dies. The TV adaptation is one of the only animes to get I-Mockery's seal of approval, and it's nowhere near as good as the comic. If you're into intricately drawn fucked-up creepy shit, you should read this comic.

I always thought Hellboy had a cool look, but never really cared enough to read it (like 90 percent of all comics). I always was more tempted to read Hitman and Hellraiser, and I didn't even read those